Effect of Eicosapentaenoic acid (EPA) supplementation on cardiovascular markers in patients with type 2 diabetes mellitus: A randomized, double-blind, placebo-controlled trial

The Role of Omega- 3 Polyunsaturated Fatty Acids in Diabetes Mellitus Management: A Narrative Review

PURPOSE OF REVIEW

Diabetes mellitus (DM) is a group of metabolic illnesses characterized by elevated levels of glucose in the bloodstream as a result of abnormalities in the generation or function of insulin. Medical Nutrition Therapy (MNT) is an essential component of diabetes management. Dietary fats are essential in both the prevention and progression of chronic diseases. Omega-3 polyunsaturated fatty acids are recognized for their advantageous impact on health. They assist in controlling blood sugar levels and lipid profile in patients with all types of diabetes. Furthermore, they reduce the occurrence of cardiovascular events and death linked to DM.

RECENT FINDINGS

After evaluating the antioxidant, anti-inflammatory, antilipidemic, and antidiabetic mechanisms of omega-3 fatty acid supplements, as well as the results from randomized controlled studies, it is clear that these supplements have positive effects in both preventing and treating diabetes, as well as preventing and treating complications related to diabetes, specifically cardiovascular diseases. However, current evidence does not support the use of omega-3 supplementation in people with diabetes for the purpose of preventing or treating cardiovascular events. People with all types of diabetes are suggested to include fatty fish and foods high in omega-3 fatty acids in their diet twice a week, as is prescribed for the general population.

Current Evidence and Future Directions of Omega-3 Supplementation and Cardiovascular Disease Risk

Omega-3 supplementation has a controversial role in the secondary prevention of cardiovascular diseases. Despite large clinical trials published over the years, the evidence of omega-3 in preventing cardiovascular diseases, especially coronary heart disease, is still inconclusive. However, recent clinical trials using higher dose of omega-3 or highly purified esters of omega-3 shows promising result, with reduction in cardiovascular death and incidence of cardiovascular disease. This review aims to summarize the possible mechanism of omega-3 in preventing cardiovascular disease and future directions of research regarding the benefit of omega-3 in cardiovascular disease.

The effects of omega-3 fatty acids in type 2 diabetes: A systematic review and meta-analysis

BACKGROUND

The effect of omega-3 polyunsaturated fatty acids (n-3 PUFAs), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on cardiovascular risk modification in type 2 diabetes and related complications remain unclear. We aim to assess the published effects of n-3 PUFA interventions on lipid risk factors in type 2 diabetes.

METHODS

We searched the literature on Pubmed, Embase, CENTRAL, and Web of Science databases in order to perform a pooled analysis of randomized clinical trials (RCTs) assessing n-3 PUFA interventions in type 2 diabetes. The primary outcomes analyzed were the effect of n -3 PUFAs on metabolic biomarkers in type 2 diabetes.

RESULTS

46 RCTs involving 4991 patients with type 2 diabetes were identified for further analysis. Analysis of results showed that n-3 PUFAs interventions significantly improved total cholesterol (TC, WMD = -0.22; 95% CI: -0.32∼ -0.11), triglyceride (TG,WMD = -0.36; 95% CI: -0.48∼-0.25), high-density lipoprotein cholesterol (HDL-C,WMD = 0.05; 95% CI: 0.02∼ 0.08), hemoglobin A1c (HbA1c, WMD = -0.19; 95% CI: -0.31∼-0.06) and C-reactive protein (CRP,WMD = -0.40; 95% CI: -0.74∼-0.07) levels compared to controls (p < 0.05). There was no significant effect on renal function, fasting blood sugar (FBS), insulin resistance (HOMA-IR), low-density lipoprotein cholesterol (LDL-C), adiponectin and leptin (p > 0.05).

CONCLUSIONS

The results of this systematic review suggest that n-3 PUFAs can improve cardiovascular risk factors in type 2 diabetes.

Role of Chemerin/ChemR23 axis as an emerging therapeutic perspective on obesity-related vascular dysfunction

Sufficient epidemiological investigations demonstrate that there is a close correlation between obesity and vascular dysfunction. Nevertheless, specific mechanisms underlying this link remain currently unclear. Given the crucial and decisive role of vascular dysfunction in multitudinous diseases, various hypotheses had been proposed and numerous experiments were being carried out. One recognized view is that increased adipokine secretion following the expanded mass of white adipose tissue due to obesity contributes to the regulation of vascular function. Chemerin, as a neo-adipokine, whose systemic level is elevated in obesity, is believed as a regulator of adipogenesis, inflammation, and vascular dysfunction via binding its cell surface receptor, chemR23. Hence, this review aims to focus on the up-to-date proof on chemerin/chemR23 axis-relevant signaling pathways, emphasize the multifarious impacts of chemerin/chemR23 axis on vascular function regulation, raise certain unsettled questions to inspire further investigations, and explore the therapeutic possibilities targeting chemerin/chemR23.

Dietary Intake of Polyphenols or Polyunsaturated Fatty Acids and Its Relationship with Metabolic and Inflammatory State in Patients with Type 2 Diabetes Mellitus

Background: The aim of the study was to evaluate the relationship between polyphenol or polyunsaturated fatty acids (PUFAs) consumption and the selected metabolic and inflammatory markers in type 2 diabetes (T2DM) patients. Methods: The study enrolled 129 diabetics (49 men, mean age 64.1 ± 9.8 years) with different amounts of polyphenol and PUFAs consumption. Results: A significant effect of polyphenol or PUFAs omega-3 consumption on fasting glucose concentration (FG) or glycated haemoglobin fraction (HbA1c) was reported. A negative association was observed between FG and total polyphenol, flavonoid, flavan-3-ol and stilbene intake. In the group with high flavonoid intake, the FG was significantly lower compared to the group characterised by low flavonoid intake. Polyphenols, except stilbenes, did not modulate HbA1c. Additionally, higher consumption of PUFAs omega-3 significantly decreased HbA1c, and the intake of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids negatively and significantly correlated with FG and HbA1c. Further analysis confirmed a significant association between EPA + DHA intake and HbA1c, with significant interactions with age and gender or with body mass index and waist-to-hip ratio. The dietary intake of polyphenols or PUFAs was independent of familial diabetes or diabetic diet application. Conclusions: Our study indicates a positive effect of high consumption of flavonoids, omega-3 PUFAs and stilbenes on the markers of carbohydrate metabolism balance and the absence of such an effect on other cardiometabolic markers and inflammatory conditions.

Prevention of Endothelial Dysfunction and Cardiovascular Disease by n-3 Fatty Acids-Inhibiting Action on Oxidative Stress and Inflammation

BACKGROUND

Prospective cohort studies and randomized controlled trials have shown the protective effect of n-3 fatty acids against cardiovascular disease (CVD). The effect of n-3 fatty acids on vascular endothelial cells indicates their possible role in CVD prevention.

OBJECTIVE

Here, we describe the effect of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) on endothelial dysfunction-caused by inflammation and oxidative stress-and their role in the development of CVD.

METHODS

We reviewed epidemiological studies done on n-3 fatty acids in CVD. The effect of DHA and EPA on vascular endothelial cells was examined with regard to changes in various markers, such as arteriosclerosis, inflammation, and oxidative stress, using cell and animal models.

RESULTS

Epidemiological studies revealed that dietary intake of EPA and DHA was associated with a reduced risk of various CVDs. EPA and DHA inhibited various events involved in arteriosclerosis development by preventing oxidative stress and inflammation associated with endothelial cell damage. In particular, EPA and DHA prevented endothelial cell dysfunction mediated by inflammatory responses and oxidative stress induced by events related to CVD. DHA and EPA also increased eNOS activity and induced nitric oxide production.

CONCLUSION

The effects of DHA and EPA on vascular endothelial cell damage and dysfunction may involve the induction of nitric oxide, in addition to antioxidant and anti-inflammatory effects. n-3 fatty acids inhibit endothelial dysfunction and prevent arteriosclerosis. Therefore, the intake of n-3 fatty acids may prevent CVDs, like myocardial infarction and stroke.

Long-chain polyunsaturated omega-3 fatty acids reduce multiple myeloma exosome-mediated suppression of NK cell cytotoxicity

BACKGROUND

Despite the advances in the treatment of multiple myeloma (MM), complete remission is usually challenging. The interactions between tumor and host cells, in which exosomes (EXs) play critical roles, have been shown to be among the major deteriorative tumor-promoting factors herein. Therefore, any endeavor to beneficially target these EX-mediated interactions could be of high importance.

OBJECTIVES

a) To investigate the effects of myeloma EXs on natural killer (NK) cell functions. b) To check whether treatment of myeloma cells with eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA), two polyunsaturated omega-3 fatty acids with known anti-cancer effects, can modify myeloma EXs in terms of their effects on natural killer functions.

METHODS

L363 cells were treated with either EPA or DHA or left untreated and the released EXs (designated as E-EX, D-EX and C-EX, respectively) were used to treat NK cells for functional studies.

RESULTS

Myeloma EXs (C-EXs) significantly reduced NK cytotoxicity against K562 cells (P ≤ 0.05), while the cytotoxicity suppression was significantly lower (P ≤ 0.05) in the (E-EX)- and (D-EX)-treated NK cells compared to the (C-EX)-treated cells. The expression of the activating NK receptor NKG2D and NK degranulation, after treatment with the EXs, were both altered following the same pattern. However, C-EXs could increase IFN-γ production in NK cells (P < 0.01), which was not significantly affected by EPA/DHA treatment. This indicates a dual effect of myeloma EXs on NK cells functions.

CONCLUSION

Our observations showed that myeloma EXs have both suppressive and stimulatory effects on different NK functions. Treatment of myeloma cells with EPA/DHA can reduce the suppressive effects of myeloma EXs while maintaining their stimulatory effects. These findings, together with the previous findings on the anti-cancer effects of EPA/DHA, provide stronger evidence for the repositioning of the currently existing EPA/DHA supplements to be used in the treatment of MM as an adjuvant treatment. EXs released from L363 (myeloma) cells in their steady state increase IFN-γ production of NK cells, while reduce their cytotoxicity against the K562 cell line (right blue trace). EXs from L363 cells pre-treated with either EPA or DHA are weaker stimulators of IFN-γ production. These EXs also increase NK cytotoxicity and NKG2D expression (left brown trace) compared to the EXs obtained from untreated L363 cells. Based on these findings, myeloma EXs have both suppressive and stimulatory effects on different NK functions depending on the properties of their cells of origin, which can be exploited in the treatment of myeloma.

Fish oil reduces subclinical inflammation, insulin resistance, and atherogenic factors in overweight/obese type 2 diabetes mellitus patients: A pre-post pilot study

OBJECTIVE

Insulin resistance-associated obesity and type 2 diabetes mellitus (T2DM) are commonly accompanied with metabolic lipid abnormalities and are characterized by hypertriglyceridemia and low HDL-c levels (atherogenic index plasma, AIP). The primary molecular mechanism that is known to cause insulin resistance is chronic low-grade inflammation. Considering that omega-3 fatty acid reduces subclinical inflammation, we hypothesized that fish oil could affect insulin resistance and AIP. Therefore, the present study evaluated the effects of fish oil supplementation on the inflammatory, insulin resistance, and atherogenic factors in overweight/obese T2DM patients.

RESEARCH DESIGNS AND METHODS

In this study, we recruited 32 overweight and/or obese patients diagnosed with T2DM for over one year and who exhibited hypertriglyceridemia. These patients received fish oil supplementation (4.0 g/day) for eight weeks. Anthropometric and body composition measurements were obtained. In addition, blood samples were collected before and after omega-3 supplementation for the evaluation of lipid profile, glycemia, insulin, and inflammation.

RESULTS

As expected, patients showed reduction in the TNFα, IL-1β, and Il-6 levels after fish oil supplementation and showed improved insulin sensitivity (HOMA-IR) without observed alterations in anthropometric and body composition. These observations were followed by reduction in the levels of triglycerides and non-esterified fatty acids, increase in HDL cholesterol levels, and a significant reduction in triglycerides/HDL-c ratio, and total cholesterol/HDL-c ratio.

CONCLUSION

Fish oil supplementation is effective in reducing the levels of proinflammatory cytokines, improving insulin resistance, and reducing atherogenic factors in overweight/obese and T2DM patients independent of weight loss.

Fish Oil and Cardiometabolic Diseases: Recent Updates and Controversies

Fatty acids derived from fish oil are long-chain omega-3 (n-3) polyunsaturated fatty acids. The important polyunsaturated fatty acids of fish oil are eicosapentaenoic acid, and docosahexaenoic acid. For decades, there has been a debate about the use of omega-3 fatty acids and their benefits on cardiovascular health. The more recent trials including the JELIS, VITAL, STRENGTH, and ASCEND trials, addressed the paucity of data of omega-3 fatty acids on primary and secondary prevention of cardiovascular events and the risk-benefit balance of these supplements. Prior to these studies, many large randomized controlled trials have shown conflicting results on the effect of polyunsaturated fatty acids in patients with prior coronary artery disease, stroke, or major vascular events. These inconsistent results warrant a better understanding of the effects of omega-3 fatty acids on the subtypes of cardiovascular diseases, and their use in primary and secondary prevention. More recently, icosapent ethyl showed a significant reduction in cardiovascular mortality and ischemic events in patients with elevated triglyceride (TG) and established cardiovascular disease or diabetes. The REDUCE-IT trial paved the way to further reduce cardiovascular risk in patients with high TG despite being on a maximally tolerated statin. The aim of this review is to discuss these recent updates on the use of various forms of fish oil, including prescription form and supplement in cardiometabolic diseases, and their surrounding controversies.

Gender-specific associations between atherogenic index of plasma and the presence and severity of acute coronary syndrome in very young adults: a hospital-based observational study

OBJECTIVE

The value of atherogenic index of plasma (AIP) as a predictive biomarker for coronary artery disease (CAD) remains controversial. In addition, whether AIP is associated with the risk of acute coronary syndrome (ACS) in very young adults has not been well established.

METHODS

We consecutively collected very young adults (≤35 years of age) undergoing coronary angiography (CAG) at Anzhen Hospital, between January 2008 and December 2017. Total of 1, 478 very young participants, including 1, 059 ACS patients and 419 non-CAD subjects, were enrolled in the present study.

RESULTS

Very young patients with ACS had higher AIP level compared with non-CAD participants (0.35 ± 0.30 vs 0.21 ± 0.33, P < 0.001). According to Gensini Score (GS) and number of lesion vessel, patients were divided into four groups, respectively. With the elevated GS score and number of lesion vessels, the AIP level increased gradually (P_{for trend} all< 0.05). Multivariate logistic regression analyses suggested that AIP remained to be independently associated with the presence of ACS and was superior to traditional lipid profiles (for AIP, OR = 2.930, 95% CI = 1.855-4.627, P < 0.001; for total cholesterol, OR = 1.152, 95% CI = 1.048-1.266, P = 0.003; for triglyceride, OR = 1.078, 95% CI = 0.991-1.172, P = 0.079; for low-density lipoprotein cholesterol, OR = 1.046, 95% CI = 1.015-1.078, P < 0.001), after adjustment for other traditional confounders. Moreover, the prevalence of ACS, acute myocardial infarction, unstable angina pectoris and the value of GS were also elevated as AIP quartiles increased (P_{for trend} < 0.001). Subgroup analysis based on gender revealed that AIP was only independently associated with the ACS risk in male.

CONCLUSIONS

AIP was independently associated with the presence and severity of ACS in very young patients in a gender-dependent manner, which might be superior to traditional lipid profiles.

Cod-Liver Oil Improves Metabolic Indices and hs-CRP Levels in Gestational Diabetes Mellitus Patients: A Double-Blind Randomized Controlled Trial

OBJECTIVE

To investigate the effects of cod-liver oil on metabolic status and high-sensitivity C-reactive protein (hs-CRP) in patients with gestational diabetes mellitus (GDM).

METHODS

This study was a randomized, double-blinded, placebo-controlled trial with the allocation ratio of 1 : 1. The contents of EPA and DHA in cod-liver oil were measured using a gas chromatograph. A total of 550 GDM patients were randomly divided into the intervention group (cod-liver oil) and the control group (placebo, mineral oil), and both groups were given regular dietary care. Glycosylated hemoglobin A1c (HbA1c), fasting plasma glucose (FPG), 2-hour plasma glucose (2hPG), lipid profiles, homeostatic model assessment insulin resistance (HOMA-IR), and hs-CRP were measured. Primary outcomes were different in HbA1c, FPG, 2hPG, and HOMA-IR between the two groups after 4-week randomization. Secondary outcomes were the blood glucose levels and perinatal complications (pregnancy-induced hypertension, polyhydramnios, premature delivery, postpartum hemorrhage, postpartum infection, premature rupture of membranes, and cesarean section) between the two groups before and after 12-16 weeks of cod-liver oil intervention from middle pregnancy to late pregnancy.

RESULTS

EPA and DHA were the main components of cod-liver oil with 76 mg/mL and 150 mg/mL, respectively. There was no significant difference for primary outcomes in the levels of HbA1c, FPG, 2hPG, HOMA-IR, and lipid profiles between the two groups (P > 0.05). For the secondary outcomes, the levels of HbA1c, FPG, 2hPG, triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol ratio (LDL-C), HOMA-IR, and hs-CRP in the intervention group were significantly lower than those in the control group (P < 0.05). The incidence of perinatal complications in the intervention group was lower than that in the control group too (P < 0.05).

CONCLUSIONS

Cod-liver oil consumption effectively reduced the levels of blood glucose, lipid levels, hs-CRP, and HOMA-IR and the incidence of perinatal complications.

Plasma fatty acid metabolic profiling coupled with clinical research reveals the risk factors for atherosclerosis development in type 2 diabetes mellitus

Many publications have reported that the incidence of atherosclerotic cardiovascular diseases is higher in patients with type 2 diabetes mellitus (T2DM) than in the non-diabetic population; however, until now, the reason has been unclear. In this study, 25 males (25/64, 39.06%) and 19 females (19/54, 35.19%) had complications with atherosclerosis after two years. To reveal the risk factors for developing atherosclerosis in patients with T2DM, plasma fatty acid metabolic profiling based on gas chromatography-mass spectrometry was combined with the analysis of clinical biochemical indices. The results of partial least squares-discriminant and canonical correlation analyses suggested that C20:0, C22:6n-3, glycosylated hemoglobin, waist circumference, and waist-to-hip ratio are likely to be closely related to T2DM complicated with atherosclerosis. Metabolomic information is a beneficial supplement to existing clinical indices and is useful in predicting the development of a patient's disease and optimizing the treatment.

FFAs metabolic profiling and clinical research were combined to reveal the risk factors for atherosclerosis development in T2DM patients.

Atherogenic Index in Type 2 Diabetes and Its Relationship with Chronic Microvascular Complications

OBJECTIVE

This study was designed to investigate risk factors related to atherogenic index of plasma (AIP), as well as the relationship between AIP and chronic microvascular complications in patients with type 2 diabetes (T2DM).

METHODS

This study included 2523 patients with T2DM who had not been treated with lipid-lowering drugs and were admitted to the Department of Endocrinology at Zhongnan Hospital, Wuhan University, during the period from January 2015 to February 2018. Anthropometric indicators were measured after overnight fasting. Low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), total cholesterol (TC), and triglyceride (TG) were detected by enzymatic analysis. Standard 75 g oral glucose tolerance testing was performed to measure 0 and 2 hr plasma levels of glucose and insulin. Insulin sensitivity was assessed with HOMA-IR.

RESULTS

Increase in AIP was associated with an increased risk for hypertension (P < 0.05), HbA_1c (P < 0.05), HOMA-IR (P < 0.05), UA (P < 0.05), and decreased eGFR levels (P < 0.05). Furthermore, AIP values directly correlated with BMI (r = 0.182, P < 0.001), waist circumference (r = 0.129, P < 0.001), blood glucose index (FBG (r = 0.153, P < 0.001), PPBG (r = 0.117, P < 0.001), and HbA_1c (r = 0.074, P < 0.001)), insulin resistance (HOMA-IR; r = 0.112, P < 0.001), and uric acid (UA, r = 0.177, P < 0.001). Multiple logistic regression analysis showed that waist circumference, HOMA-IR, FBG, systolic blood pressure, and UA were independent risk factors for AIP (all P < 0.05). The prevalence of diabetic neuropathy and metabolic syndrome was significantly higher among patients with higher AIP.

CONCLUSION

AIP represents a clinically convenient indicator for the detection of T2DM with high risk of complications and associated diseases and thus is a good predictor and indicator for follow-up monitoring in the treatment of patients with high-risk type 2 diabetes.